Altitude controlled pressure



'w. J. JAcoBssoN March 9, 1943.

' ALTITUDE CONTROLLED PRESSURE nzeuwrox Filed July 20, 1940 I INVENTORWILGOT J'JACOBSSON ATTORNEY Patented Mar. 9, 1943 ALTITUDE CONTROLLEDPRESSURE REGULATOR, j

Wilgot J. Jacobsson, Plainfield, N. J assignor to Union Carbide andCarbon Corporation, a corporation of New York Application anuy zo, 1940,Serial No. 346,473

4 Claims. (Cl. 137-153) This invention relates to apparatus forsupplying oxygen for high altitude operation of aircraft and similarpurposes, and more particularly to a unitary two-stagealtitude-controlled pressure regulator for reducing the pressure of'theoxygen to a relatively low value.

In high altitude flying, oxygen, in addition to that available from theatmosphere, must be supplied to the occupants of an airplane tocompensate for the decreased density of the atmospheric oxygen due tothe increased rarity of the atmosphere. The additional amount of oxygenrequired is substantially proportional to the altitude at which theaircraft is flying. As bothspace and weightare at a premium in aircraft,the bulk and weight of the oxygen sup- .ply and associated regulatingapparatus must be kept as small as possible. For this reason, the oxygenusually is supplied in cylinders in which the oxygen is compressed underrelatively high pressure. In order to relieve the operator of theairplane fromthe necessity of controlling the supply of oxygen inaccordance with changes in altitude, it has hitherto been pro- :posed touse automatic apparatus for supplying varying quantities of oxygen tothe interior of the aircraft in accordance with changes in altitude,which changes are reflected in corresponding changes in the atmosphericpressure.

When it is attempted to reduce the oxygen pressurewin a single stageiromvthe relatively high cylinder pressure to the relatively lowpressure at which the oxygen is supplied to oxygen masks or otherconsuming appliances, wide fluctuations in the pressure of the suppliedoxygen occur.- It has therefore been proposed to use two or morepressure-reducing devices in series to reduce the pressure of the oxygenin more than one stage. However, this increases the number of pieces ofregulating apparatus and connections, with a corresponding increase inbulk and weight and a decrease in the available spacein the airplane.

The automatic means for controlling the supply of oxygen in accordancewith changes in altitude and atmospheric pressure have usually comprisedatmospheric pressure responsive regulators which control the supply ofthe oxygen. Howevenno satisfactory means for supplying oxygen to theconsuming apparatus under relatively steady conditions, which apparatusis also light in weight and economical of space, has hitherto beendevised. I

. It is therefore among the objects of this invention to provide acompact, light weight, oxygen supply and regulating apparatus fordelivering oxygen, from a cylinder of oxygen'compressed under relativelyhigh pressure, ,to a

consuming device, such as on oxygen-mask, in which the oxygen isconsumedat relatively'low pressure; to provide a unitary two-stageoxygenpressureregulator in which'the pressure of the oxygen is reduced fromthe cylinder pressure to an intermediate pressure and from the,intermediate pressure to a low pressure suitable for'delivery to theconsuming apparatus; to provide a two-stage oxygen pressure regulator inwhich the pressure in thelow pressure stage is controlled in accordancewith variations, in atmospheric pressure corresponding to variations inaltitude; and to provide a simple, compact,

light Weight and eflicient oxygen supplyappae i Fig. 2 is a section onthe line 22 of Fig. 1,

looking in the direction of the arrows. l

The objects of the. invention may be accom plished' by providing atwo-stage fluid pressure regulator and reducing valve comprising aonepiece valve body separated intolia relatively small high pressurestage or fluid chamber, a

relatively small intermediate pressure stage or fluid chamber and arelatively largelow pressure stage or fluid chamber. Means are providedto connect the high pressurechamber to a compressed oxygen tank outletand'it'o connect the low pressure chamber toa consuming device, such asan aviators' oxygen mask. Valve means are'provided between thehighpressure chamber and the intermediate pressure chamber'to controlthe rate of .delivery' of; oxygen between the two chambers in accordancewith pressure conditionsrexisting in the intermediate pressure chamber.,Other valve meanspreferably controlled by anatmospheric-pressureleresponsiveunit readily attachable to andremovablefrom the valve body, are provided for controlling the rate of flow ofoxygen fromthe intermediate-pressure chamber totli'e low pressurechamber in accordance vwith variationsin atmospheric pressure,corresponding to changes in altitude; If desired, indicating gauges. maybe connected to the .highLpr-essure stageor chamber and to the tolow'pressure-stage or chamber...

sure stage or chamber I8 in the valve body I0" through an oxygen inletnipple which may be attached to a compressed oxygen tank outlet by meansof a union coupling nut 22.

The passage of the oxygen from the high pres sure stage I8 to theintermediate pressure stage I4 is controlled by a valve 24 operated inresponse to the pressure in the intermediate stage. The valve 24 seatson a valve seat 26 maintained in place by a valve seat plug or bushing28, through which the stem 30 of the valve 24 passes. The valve seatbushing is provided with a central cavity 32 to receive a spring 34,which fits around the valve stem 30 and rests on the bottom wall of thecavity. A diaphragm attaching screw 36 is provided with annular slottedprojections 38, which fit loosely into the cavity of the valve seatbushing 28 around the spring 34, W

and with a centrally threaded bore 46 into which the end of the valvestem 30 is screwed. The parts so assembled are secured in the valve bodyI!) by the engagement of the external threads on the valve bushing orplug 28 with threads in the reduced pressure chamber I4 where anenlarged space may be provided for the spring without increasing thesize of the pressure chamber. Thisrloc ation of the valve closing springwithin the'pressure chamber permits the use of a larger diameter springcoil 34 and a proportionately shorter spring which reduces the length ofthe regulator without increasing the size of the regulator, and at thesame time the spring 34 does not materially obstruct the passage of gasthrough the regulator.

The outer end of the gas chamber I4 of the intermediate pressure stageis closed by a circular diaphragm 44 resting on a shoulder 46 on thevalve body III at the end of the chamber I4. The diaphragm 44 has acentral aperture therein which receives the threaded extension 48 of theattachingscrew 36, and the diaphragm isattached to the attaching screw36 between a flange '50 on the screw and a diaphragm clamping nut 52screwed on the extension 48. A coiled spring 54 rests on the clampingnut 52 and is compressed between the nut and the inside of the outer endof a hollow cap 56. The inner end of cap 56 is provided with screwthreads, and isscrewed into the diaphragm cavity 58 to hold the rim orthe diaphragm 44 in leak-proof contact with the shoulder 46 on the valvebody I0 and to compress the'spring 54 against the action of thediaphragm "44 and the smaller spring'34 in thevalve bushing cavity.A'hole 60 is provided in 'thetop of the cap to permit the ingress andegress of air to and from the inside of the cap 56. The apparatus thusfar described is similar to that shown and described in Patent No.2,057,133, issued in the names of C. K. Bryce and H. W. Jones on October13, 1936.

In accordance with the principles of the invention, the flow of gas fromthe intermediate pressure chamber I4 into the low pressure chamber I6 iscontrolled in accordance with changes in atmospheric pressure due tochanges in altitude. An oxygen inlet passage 66 in the valve body I6extends from the gas chamber I4 to a chamber 68 which receives a valveIII for controlling the passage of oxygen from the intermediate pressurestage I4 to the low pressure stage I6. ,The valve I0 seats on a valveseat I2 maintained in place by a valve seat bushing or plug I4, throughwhich stem I6 of the valve I0 passes. The valve seat plug I4 is providedwith a central cavity "I8 to receive a spring 80. The construction ofthis valve is similar to the construction'of the valve whichcor'itrolsthe gas from the high pressure stage to the intermediate pressure stage.The valve 16, valve seat I2, valve plug 14, spring 80 and diaphragmattaching screw 62 may be similar to or duplicates of the correspondingparts used in the intermediate pressure stage and are assembled inchamber I6 of the low pressure stage in the same manner as thecorresponding parts are assembled in the intermediate pressure stage.The outer wall of the low pressure fluid or oxygen chamber I6 is formedby a flexible diaphragm 84 whose outer perimeter is clamped between theend wall of the to variationsof oxygen pressure in chamber I6.

The plate 92 is screwed on the threaded end of the screw-82.

Engaging the fiange94 is a corresponding flange 93 on a rigid member I66forming the end wall of an expansible and contractible bellows I02. Thebellows includes a flexible wall III4 which may be secured at one end tothe rigid member I06, as by soldering, and at the other end to a secondrigid member 166 relatively fixed in position and forming the other endwall of the bellows. Disposed in the bellow I62 is a spring I08 forapurpose-described hereinafter. A hollowcap or casing H0 is set over andencloses the bellows I62 and is screwed to the clamping ring "88. Thecap H6 is provided with a hole I I2 whereby the interior of the cap isexposed to atmospheric pressure to allow atmospheric pressure to affectthe bellows I 62. The diameter of the chamber I6 of the low pressurestage and the eifective area of diaphragm '84 that closes the chamberare made larger than the corresponding elements of the intermediatepressure stage due to the lower pressure maintained in the low pressurechamber I6, and in order toob'tain a more accurate regulation of thepressure in the latter chamber.

The clamping ring 88, bellows I 62, spring IIIB,

and cap or casing III] form an atmospheric-pressure-responsive unitwhich is readily attachable "to and. removable from the valve body I6.For

this purpose, it will be noted that the internal diameter of theradially inwardly projecting flange 80 of the ring 88 is less than theexternal diameter of the rigidmember I forming the end wall .of thebellows I02. Thereby, when the ring 80 15 unscrewed from the body I0,the unit will be maintained in assembled relation. When the unit iscoupled to the body I0, the flange 80 on the ring 88 acts as meansoperative to clamp the rim of the diaphragm 84 in sealing relation tothe chamber I8; When the unit is removed from the body I0, the ring actsas means carried by the cap andoperable to retain the bellows I02 andthe spring I08 within the cap or casing IIO. An arcuategroove I I4 iformed in the partition I2 of the valve body I0 and extends from thehigh pressure stage inlet or nipple 20 around a portion of thecircumference of the valve body. A similar groove H6 is formed in thevalve partition I2 and communicates with the low pressure stage I6.The'high pressure groove H4 is separated from the low pressure groove H0by partitions H8 in the valve body. A high pressure gauge I20may beconnected to the high pressuregroove H4, and a safety plug I24 and a 10W1 pressure gauge I22 are connected to the low pres- The diaphragm springof the intermediate pressure stage is designed to reduce the supplypressure to asubstantially lower pressure which exceeds the maximumpressure delivered to the low pressure stage but is preferablymaintained very low so that the effective load maintained on theintermediate pressure diaphragm, having a smaller effective area thanthe effective area of the low pressure diaphragm, will be less than theeffective load on, the low pressure diaphragm.

This is done in order that a smaller diaphragm spring as well as asmaller diaphragm may be used in the intermediate pressure stage than isrequired in the low pressure stage. The pressure maintained in theintermediate pressure stage may be varied by changing the spring 54 forone of different strength. The spring 54 is made non-adjustable toprevent the operator of the regulator from changing the pressure settingof the intermediate pressure stage and thereby allow excessive pressureto accumulate in the intermediate pressure stage. The oxygen, under theexcess pressure, may rush into the low pressure stage and injure thediaphragm 84 therein vbefore the valve I0 can close the passage whichconnects the two stages.

The bellows I02 and the spring I08 therein are so designed that thebellows will expand with a decrease in atmospheric pressure to graduallyincrease the pressure exerted on the diaphragm 84 over a wide range inaltitude. The set screw I30 is provided for adjusting the low stageregulator so that it will beginto operate at the desired altitude. Asthe relatively fixed position of the end wall I00 is changed and thebellows I02 and the spring I08 are compressed by the adjusting screwI30, the device will begin to deliver oxygen at a lower altitude. Hence,by a suitable adjustment of the screw I30, oxygen delivery may be madeto commence at any selected altitude.

As the altitude of the aircraft, or other means, in which the regulatoris disposed increases beyond the altitude for which the screw I30 hasbeen set, the valve will begin to open under the action of the bellowsI02 and the spring "I08, and the delivery of oxygen at the desiredpressure to the nipple I26 will begin. As the altitude increases, theatmospheric pressure decreases and the Valve I0 will thus be opened morewidely due to the action of the bellows I02 and'spring I08. As thedelivery pressure varies inversely as the atmospheric pressure, thedelivery pressure of the oxygen will also increase. These two factorsre-- sult in an increase in the volume of oxygen delivered as thealtitude increases.

The restricting orifice I28, located in nipple I20, acts as a pressureequalizing means preventing sudden changes of pressure in the chamber I0from being immediately reflected in the delivery linesconnected to thenipple I20. This assures an even regulated, flow of oxygen at a desiredvpressure and volume .corresponding to the given altitude.

In reducing the high pressure of oxygen in the pressure tank to theintermediate pressure, the gradually decreasing tank pressureacting onthe exposed surface of the intermediate pressure stage controlling valve24 causes the valve to open and close in response to a pressure greaterthan that at which it responded when the tank was under a higherpressure, and therefore, the pressure maintained in the intermediatepressure chamber increases with a given spring 54 as the gas pressure inthe tank decreases. Sometimes, the moisture in the oxygen freezes as itexpands from the highpressure stage to the intermediate pressure stage,and these cold pellets clog the opening and produce pressure impulses inthe reduced pressure. While these variations in pressure in theintermediate pressure stage, are great enough to deleteriously affectthe character of the oxygen flow from the low pressure stage, they arenot great enough to materially affect the regulating action of the lowpressure stage control valve I0. The oxygen absorbs suflicient heat atthe intermediate pressure stage to melt any pellets of frozen moisturethat may have been formed and the reduction in pressure between theintermediate pressure stage and the low pressure stage is not sufficientto cause the reformation of these pellets. Due to the substantiallyconstant reduced pressure maintained in theintermediate pressure stage,the oxygen passes therefrom to the low pressure stage without producingany irregular action in the low pressure stage control valve, such as isproduced in the action of the intermediate pressure stage control valve.The low pressure control valve is therefore capable of maintaining, inthe low pressure stage, a pressure corresponding to a given altitude.

It will be noted that the inlet to and the discharge from the valvecasing, and the pressure gauges and the safety plugs, are convenientlyarranged around the circumference of the valve casing in the centralplane of the partition I2 in the valve body I 0. Also, the intermediatepressure stage and the low pressure stage are located at opposite sidesof this plane. This construction gives a compact arrangement. of theparts and places the center of gravity of the regulator close to thelongitudinal axis of the compressed oxygen tank when the inlet of theregulator is attached to the outlet from the tank. This feature resultsin a considerable saving of space in the aircraft. Correspondingly, theincorporation of both of the pressure stages in a single unitary bodyreduces the weight of the apparatus necessary to be carried whilepermit-- ting suflicient regulation of the flow of oxygen at allaltitudes.

If desired, variations in the effect of the bellows due to temperaturechanges may be substantially overcome by exhausting air from the bellowsand making the spring I08 suiliciently heavy to overcome the externalpressure.

While a preferred form of the invention has been shown, it should beunderstood that changes may be made in the form shown without departingfrom the scope of the invention as defined in the appended claims.

What is claimed is:

1. A fluid pressure regulator comprising, in combination, a body formedwith a fluid chamber; a flexible diaphragm forming one wall of saidchamber; a valve secured to said diaphragm and controlling the flow offluid into said chamber; a clamping ring threadedly secured to said bodyand having a radially inwardly projecting flange overlying the rim ofsaid diaphragm and holding the latter in sealing engagement with saidbody to seal said chamber; a backing plate secured to said diaphragm andformed with an annular flange; a resilient bellows having two rigid endwalls, one end wall being formed with an annular flange interfitting theannular flange on said backing plate, said bellows being responsive tochanges in atmospheric pressure; a spring in said bellows engaging saidend walls; a hollow cap enclosing said bellows and threadedly secured tosaid clamping ring, the interior of said cap being exposed toatmospheric pressure; and a screw threaded through the end wall of saidcap and engaging the other end wall of said bellows and operable toadjust the compression of both said spring and said bellows.

2. An altitude-controlled oxygen supply regulator comprising, incombination, a body provided with an oxygen inlet, an oxygen chamberhaving an open end, an oxygen outlet for said chamher, and a valvecontrolling the flow of oxygen from said inlet into said chamber; andmeans for actuating said valve, such means comprising a flexiblediaphragm operatively connected to said valve and responsive tovariations of th oxygen pressure in said chamber, a ring detachablysecured to said body and clamping the margin of said diaphragm againstthe edge extending around said open end of said chamber, a capdetachably secured to said ring and having its interior exposed toatmospheric pressure, an expansible and contractible bellows in said capand responsive to changes in atmospheric pressure, a spring within saidbellows and tending to expand said bellows, means carried by said capand operable to adjust the position of one end of said bellows and thecorresponding end of the spring therein, both said spring and saidbellows being adapted to bear against said diaphragm to actuate saidvalve in response to changes in atmospheric pressure, a portion of saidring projecting within said cap and adapted to engage said bellows andretain the latter and said spring within said cap when said ring andsaid cap are detached as a unit from said body.

3. For use with a fluid supply regulator having a body provided with achamber, one wall of which comprises a flexible,valve-position-controlling diaphragm, an atmospheric-pressure-responsiveunit readily attachable to and removable from said body comprising, incombination, a cap adapted to be detachably secured to said body andhaving its interior exposed to atmospheric pressure; a bellows disposedin said cap and both expansible and contractible in response to changesin atmospheric pressure; a spring in said bellows and tending to expandsaid bellows; means carried by said cap and operable to adjust theposition of one end of said bellows and the corresponding end of thespring therein; both said bellows and said spring being adapted to bearagainst said diaphragm when said cap is attached to said body, toactuate said diaphragm in response to changes in atmospheric pressure;and means carried by said cap and operable to retain both said bellowsand said spring within said cap when said unit is removed from theregulator.

4. An atmospheric-pressure-responsive unit, as claimed in claim3,wherein the last-named means which is operative to retain both thebellows and the spring within the cap also is operative to clamp the rimof said diaphragm in sealing relation to said chamber in said body whensaid unit is attached to said body.

WILGOT J. J ACOBSSON.

